1. Blasse G 1964Philips Res. Rep. Suppl. 3
2. Bradley F N 1971Materials for magnetic functions (New York: Hayden) p. 78
3. Buerger M G 1960Crystal structure analysis (New York: Wiley)
4. Cullity B D 1959Elements of X-ray diffraction (Reading, Mass: Addison Wesley)
5. Furuhashi H, Inagari M and Naka S 1973J. Inorg. Nuclear Chem. 35 3009